Jet ski incidents such as hooning — speeding or behaving in a dangerous manner — have become a daily occurrence, spokeswoman Kate Millar said.

Plain clothes officers will work alongside uniformed water police, patrolling the foreshore and looking out for any dangerous behaviour on the water.

Senior Sergeant Steve Towers said water police were fed up with jet ski riders ignoring water safety rules. He said that police would be keeping an eye on high-powered vessels until the riders "get the message".

"It is frustrating to continually see this type of behaviour, day in and out, despite the obvious risks," Sergeant Towers said.

"You are operating a high-powered vessel that weighs 400 kilograms or more. Think about the impact that you can have if you collide with another boater — or worse, a swimmer."

Sergeant Towers said police recognised that many jet ski riders behaved safely, but that there were "far too many rogues out there who are ruining it for everyone".

"It's simple: stay out of the swimming zones, head out 200 metres from shore, and stay more than 50 metres away from other vessels and people," he said.

In October, a 23-year-old Roxburgh Park man, Ivan Maqi, was charged over the death of a 51-year-old swimmer at Lagoon Pier, near Port Melbourne, in 2012.

The South Melbourne man died in hospital of head injuries several days after the incident.

It was alleged that Mr Maqi, who was charged with culpable driving causing death, was speeding at the time and riding in a restricted area.